Who is working on explaining the knowledge encoded into machine learning models?
I have one concept, which allows to structure knowledge gathered by a ML system in both categorical and algorithms-like structure.

The key idea here is that we contain in our minds some network-like structure in our minds, which helping us not only to classify some data, but also to form an abstract meaning about text or message.

Other than that, in opposite to our minds, it looks like this solution can produce these structures in readable for us forms.